Personal display devices make it possible to provide image content to a viewer in applications where the use of conventional display screens would be an encumbrance. Head-mounted devices (HMDs), such as display goggles, are being considered as a useful type of wearable personal display device usable in a variety of fields, with applications ranging from military, medical, dental, industrial, and game presentation, among others. Stereoscopic imaging, with its enhanced spatial representation and improved presentation of relevant detail, can be particularly useful for presenting images that are more lifelike and that show depth information more accurately than can be possible with 2-dimensional (2-D) flat displays.
Although a number of advances have been made for improving usability, size, cost, and performance of wearable display devices, there remains considerable room for improvement. In particular, imaging optics that present the electronically processed images to the viewer have been disappointing. Conventional design approaches have proved difficult to scale to the demanding size, weight, and placement requirements, often poorly addressing optical problems related to field of view and distortion, eye relief, pupil size, and other factors.